Different factions fight to take over themselves.
The problem is that the line of succession is left in doubt and that leaves the throne open to take over by other parties. Often the family that is left is in danger from the people who want the throne.
If the king leaves no heir, that means there is no king, no one to watch over the people, and no one to take over. It can cause problems with people fighting to be able to take over, crimes committed because of a vacuum in leadership, and a higher potential for an inconsistent and violent government transitional period.
he hunted alot and fought in wars
His heirs were his infant son and brain-damaged brother, neither able to exercise control of the vast empire. His generals seized parts of it and fought for supremacy, forming their own kingdoms.
heir --- It is not an Heir. An Heir is what you call the people who receive something from a will or a trust. A person who dies leave a will is a Testator.
On that date, King Edward ("The Confessor") of England died leaving no clear heir. This ignited the three-way rivalry between William the conqueror, Harold the king's brother, Harald the King of Norway.
An 'heir apparent' is the person who will become the next king or queen.
He was his childless brother King Richard I's (The Lionheart) heir.
Traditionally, when a king dies, the heir to his throne is his eldest son.
its when the son is made king
Because her father died without leaving a male heir.
Sometimes, the causes seem to be obvious: a neighboring kingdom invades and conquers the state, a king dies without leaving an heir, or the military turns upon the ruler and ousts him.